Spring Semester 2026 Phlebotomy Technician Certification
Practice Questions and Answers | Complete Phlebotomy Study
Guide with Verified Questions, Detailed Rationales, Venipuncture
Techniques, Specimen Collection, Infection Control, Patient
Identification, Order of Draw, Safety Procedures, Laboratory
Practices & CPT Certification Exam Prep
Question 1: What is the primary purpose of the tourniquet during a venipuncture
procedure?
A. To sterilize the puncture site
B. To make veins more visible and palpable by restricting venous return
C. To prevent arterial blood flow
D. To numb the area before needle insertion
CORRECT ANSWER: B. To make veins more visible and palpable by restricting
venous return
Rationale: The tourniquet is applied to restrict venous blood flow back to the heart,
causing veins to distend and become easier to locate and puncture. It should not be left
on for more than one minute to prevent hemoconcentration.
Question 2: Which gauge needle is most commonly used for routine adult
venipuncture?
A. 18 gauge
B. 21 gauge
C. 25 gauge
D. 30 gauge
CORRECT ANSWER: B. 21 gauge
Rationale: A 21-gauge needle is the standard size for routine venipuncture in adults. An
18-gauge is typically used for blood donation, while 23-25 gauge needles are used for
pediatric or fragile veins.
Question 3: What is the correct order of draw for a serum separator tube (SST), a
sodium citrate tube, and an EDTA tube?
A. SST, Sodium Citrate, EDTA
B. Sodium Citrate, SST, EDTA
C. EDTA, Sodium Citrate, SST
D. Sodium Citrate, EDTA, SST
CORRECT ANSWER: B. Sodium Citrate, SST, EDTA
Rationale: The order of draw prevents cross-contamination of additives. Sodium citrate
(light blue) is drawn first among these to ensure accurate coagulation results. SST
,(gold/tiger) follows, and EDTA (lavender) is drawn last among these three to prevent
potassium or EDTA contamination affecting other tests.
Question 4: Which antiseptic is preferred for cleaning the site before a routine
venipuncture?
A. Hydrogen peroxide
B. 70% Isopropyl alcohol
C. Betadine (Povidone-iodine)
D. Sterile water
CORRECT ANSWER: B. 70% Isopropyl alcohol
Rationale: 70% isopropyl alcohol is the standard antiseptic for routine venipuncture.
Betadine is reserved for blood cultures to ensure sterility, while hydrogen peroxide and
sterile water are not effective skin antiseptics for this purpose.
Question 5: What complication is most likely if the tourniquet is left on for longer
than one minute?
A. Hemolysis
B. Hemoconcentration
C. Hematoma
D. Nerve damage
CORRECT ANSWER: B. Hemoconcentration
Rationale: Prolonged tourniquet application causes fluid to shift from the intravascular
space to the interstitial space, concentrating cells and large molecules in the blood.
This can falsely elevate test results for proteins, lipids, and certain ions.
Question 6: Which tube additive prevents glycolysis and is used for glucose
testing?
A. EDTA
B. Heparin
C. Sodium Fluoride
D. Clot Activator
CORRECT ANSWER: C. Sodium Fluoride
Rationale: Sodium fluoride inhibits enolase, an enzyme required for glycolysis, thereby
preserving glucose levels in the sample. It is typically found in gray-top tubes.
Question 7: What is the recommended angle of insertion for a standard
venipuncture using an evacuated tube system?
A. 5 to 10 degrees
B. 15 to 30 degrees
C. 45 to 60 degrees
D. 90 degrees
,CORRECT ANSWER: B. 15 to 30 degrees
Rationale: Inserting the needle at a 15 to 30-degree angle allows for proper entry into
the vein without going through the posterior wall. Angles less than 15 degrees may
cause the needle to slide over the vein, while angles greater than 30 degrees increase
the risk of penetrating through the vein.
Question 8: Which of the following is a universal precaution when handling blood
specimens?
A. Wearing gloves only when the patient has a known infection
B. Recapping needles immediately after use
C. Treating all blood and body fluids as potentially infectious
D. Disposing of sharps in regular trash bins
CORRECT ANSWER: C. Treating all blood and body fluids as potentially infectious
Rationale: Standard Precautions require healthcare workers to treat all human blood
and certain body fluids as if they are known to be infectious for HIV, HBV, and other
bloodborne pathogens, regardless of the patient's diagnosis.
Question 9: What is the primary function of EDTA in a lavender-top tube?
A. To activate clotting
B. To bind calcium and prevent clotting
C. To preserve glucose levels
D. To separate serum from cells
CORRECT ANSWER: B. To bind calcium and prevent clotting
Rationale: EDTA (Ethylenediaminetetraacetic acid) chelates calcium ions, which are
essential for the coagulation cascade. By removing calcium, it prevents the blood from
clotting, making it ideal for hematology tests like CBCs.
Question 10: Which vein is generally considered the first choice for venipuncture in
the antecubital fossa?
A. Basilic vein
B. Cephalic vein
C. Median cubital vein
D. Dorsal metacarpal vein
CORRECT ANSWER: C. Median cubital vein
Rationale: The median cubital vein is typically large, well-anchored, and less painful to
access because it lies over connective tissue rather than nerves or arteries. It is the
preferred site for routine venipuncture.
Question 11: What is the correct procedure if a patient faints during a blood draw?
, A. Continue the draw to finish quickly
B. Remove the tourniquet and needle immediately, then assist the patient
C. Shake the patient to wake them up
D. Leave the room to get help
CORRECT ANSWER: B. Remove the tourniquet and needle immediately, then assist
the patient
Rationale: Patient safety is the priority. The needle and tourniquet must be removed to
prevent injury if the patient convulses or falls. The phlebotomist should then lower the
patient’s head or have them lie down to restore blood flow to the brain.
Question 12: Which tube color top contains heparin?
A. Light Blue
B. Green
C. Lavender
D. Gray
CORRECT ANSWER: B. Green
Rationale: Green-top tubes contain heparin (either lithium, sodium, or ammonium
heparin), which acts as an anticoagulant by inhibiting thrombin. They are used for
plasma chemistry determinations.
Question 13: What is the maximum number of attempts a phlebotomist should
make before seeking assistance?
A. One
B. Two
C. Three
D. Four
CORRECT ANSWER: B. Two
Rationale: Most institutional policies and certification standards recommend no more
than two attempts per phlebotomist. If unsuccessful, another qualified individual
should attempt the draw to minimize patient trauma and anxiety.
Question 14: Which of the following tests requires strict fasting for 8–12 hours?
A. Complete Blood Count (CBC)
B. Lipid Profile
C. Thyroid Stimulating Hormone (TSH)
D. Hemoglobin A1c
CORRECT ANSWER: B. Lipid Profile
Rationale: Fasting is required for lipid profiles (cholesterol, triglycerides) because
recent food intake can significantly alter triglyceride levels and affect the calculation of
LDL cholesterol. CBC, TSH, and HbA1c do not strictly require fasting.
Practice Questions and Answers | Complete Phlebotomy Study
Guide with Verified Questions, Detailed Rationales, Venipuncture
Techniques, Specimen Collection, Infection Control, Patient
Identification, Order of Draw, Safety Procedures, Laboratory
Practices & CPT Certification Exam Prep
Question 1: What is the primary purpose of the tourniquet during a venipuncture
procedure?
A. To sterilize the puncture site
B. To make veins more visible and palpable by restricting venous return
C. To prevent arterial blood flow
D. To numb the area before needle insertion
CORRECT ANSWER: B. To make veins more visible and palpable by restricting
venous return
Rationale: The tourniquet is applied to restrict venous blood flow back to the heart,
causing veins to distend and become easier to locate and puncture. It should not be left
on for more than one minute to prevent hemoconcentration.
Question 2: Which gauge needle is most commonly used for routine adult
venipuncture?
A. 18 gauge
B. 21 gauge
C. 25 gauge
D. 30 gauge
CORRECT ANSWER: B. 21 gauge
Rationale: A 21-gauge needle is the standard size for routine venipuncture in adults. An
18-gauge is typically used for blood donation, while 23-25 gauge needles are used for
pediatric or fragile veins.
Question 3: What is the correct order of draw for a serum separator tube (SST), a
sodium citrate tube, and an EDTA tube?
A. SST, Sodium Citrate, EDTA
B. Sodium Citrate, SST, EDTA
C. EDTA, Sodium Citrate, SST
D. Sodium Citrate, EDTA, SST
CORRECT ANSWER: B. Sodium Citrate, SST, EDTA
Rationale: The order of draw prevents cross-contamination of additives. Sodium citrate
(light blue) is drawn first among these to ensure accurate coagulation results. SST
,(gold/tiger) follows, and EDTA (lavender) is drawn last among these three to prevent
potassium or EDTA contamination affecting other tests.
Question 4: Which antiseptic is preferred for cleaning the site before a routine
venipuncture?
A. Hydrogen peroxide
B. 70% Isopropyl alcohol
C. Betadine (Povidone-iodine)
D. Sterile water
CORRECT ANSWER: B. 70% Isopropyl alcohol
Rationale: 70% isopropyl alcohol is the standard antiseptic for routine venipuncture.
Betadine is reserved for blood cultures to ensure sterility, while hydrogen peroxide and
sterile water are not effective skin antiseptics for this purpose.
Question 5: What complication is most likely if the tourniquet is left on for longer
than one minute?
A. Hemolysis
B. Hemoconcentration
C. Hematoma
D. Nerve damage
CORRECT ANSWER: B. Hemoconcentration
Rationale: Prolonged tourniquet application causes fluid to shift from the intravascular
space to the interstitial space, concentrating cells and large molecules in the blood.
This can falsely elevate test results for proteins, lipids, and certain ions.
Question 6: Which tube additive prevents glycolysis and is used for glucose
testing?
A. EDTA
B. Heparin
C. Sodium Fluoride
D. Clot Activator
CORRECT ANSWER: C. Sodium Fluoride
Rationale: Sodium fluoride inhibits enolase, an enzyme required for glycolysis, thereby
preserving glucose levels in the sample. It is typically found in gray-top tubes.
Question 7: What is the recommended angle of insertion for a standard
venipuncture using an evacuated tube system?
A. 5 to 10 degrees
B. 15 to 30 degrees
C. 45 to 60 degrees
D. 90 degrees
,CORRECT ANSWER: B. 15 to 30 degrees
Rationale: Inserting the needle at a 15 to 30-degree angle allows for proper entry into
the vein without going through the posterior wall. Angles less than 15 degrees may
cause the needle to slide over the vein, while angles greater than 30 degrees increase
the risk of penetrating through the vein.
Question 8: Which of the following is a universal precaution when handling blood
specimens?
A. Wearing gloves only when the patient has a known infection
B. Recapping needles immediately after use
C. Treating all blood and body fluids as potentially infectious
D. Disposing of sharps in regular trash bins
CORRECT ANSWER: C. Treating all blood and body fluids as potentially infectious
Rationale: Standard Precautions require healthcare workers to treat all human blood
and certain body fluids as if they are known to be infectious for HIV, HBV, and other
bloodborne pathogens, regardless of the patient's diagnosis.
Question 9: What is the primary function of EDTA in a lavender-top tube?
A. To activate clotting
B. To bind calcium and prevent clotting
C. To preserve glucose levels
D. To separate serum from cells
CORRECT ANSWER: B. To bind calcium and prevent clotting
Rationale: EDTA (Ethylenediaminetetraacetic acid) chelates calcium ions, which are
essential for the coagulation cascade. By removing calcium, it prevents the blood from
clotting, making it ideal for hematology tests like CBCs.
Question 10: Which vein is generally considered the first choice for venipuncture in
the antecubital fossa?
A. Basilic vein
B. Cephalic vein
C. Median cubital vein
D. Dorsal metacarpal vein
CORRECT ANSWER: C. Median cubital vein
Rationale: The median cubital vein is typically large, well-anchored, and less painful to
access because it lies over connective tissue rather than nerves or arteries. It is the
preferred site for routine venipuncture.
Question 11: What is the correct procedure if a patient faints during a blood draw?
, A. Continue the draw to finish quickly
B. Remove the tourniquet and needle immediately, then assist the patient
C. Shake the patient to wake them up
D. Leave the room to get help
CORRECT ANSWER: B. Remove the tourniquet and needle immediately, then assist
the patient
Rationale: Patient safety is the priority. The needle and tourniquet must be removed to
prevent injury if the patient convulses or falls. The phlebotomist should then lower the
patient’s head or have them lie down to restore blood flow to the brain.
Question 12: Which tube color top contains heparin?
A. Light Blue
B. Green
C. Lavender
D. Gray
CORRECT ANSWER: B. Green
Rationale: Green-top tubes contain heparin (either lithium, sodium, or ammonium
heparin), which acts as an anticoagulant by inhibiting thrombin. They are used for
plasma chemistry determinations.
Question 13: What is the maximum number of attempts a phlebotomist should
make before seeking assistance?
A. One
B. Two
C. Three
D. Four
CORRECT ANSWER: B. Two
Rationale: Most institutional policies and certification standards recommend no more
than two attempts per phlebotomist. If unsuccessful, another qualified individual
should attempt the draw to minimize patient trauma and anxiety.
Question 14: Which of the following tests requires strict fasting for 8–12 hours?
A. Complete Blood Count (CBC)
B. Lipid Profile
C. Thyroid Stimulating Hormone (TSH)
D. Hemoglobin A1c
CORRECT ANSWER: B. Lipid Profile
Rationale: Fasting is required for lipid profiles (cholesterol, triglycerides) because
recent food intake can significantly alter triglyceride levels and affect the calculation of
LDL cholesterol. CBC, TSH, and HbA1c do not strictly require fasting.
